Beta-blockers are so called because they block the action of epinephrine and norepinephrine on beta-adrenergic(BA) receptors. Epinephrine and norepinephrine are better known to some as adrenaline and noradrenaline. They are hormones responsible for modulating the “fight or flight” response of an organism. This response occurs when an organism is faced with a stressful situation, and results in an increase in both heart rate and force of myocardial contraction, along with the constriction of blood vessels in many parts of the body. Understandably, this puts a strain on the heart, a strain which beta-blockers seem to mitigate by blocking adrenaline from binding to BA receptors and reducing the intensity of the fight or flight response.

BA receptors are located throughout the body, however, and it has never been completely understood exactly where beta-blockers work to improve heart health. It was assumed (although not proven) that most of their action was on receptors in the heart. It was thought that the antagonistic effects of beta-blockers on these receptors inhibited the action of epinephrine, lowering heart rate, dilating blood vessels, and thus having an antihypertensive effect.

This doesn’t mean beta-blockers don’t work on the heart as well. It does, however, provide an impetus for further research into their mechanism. For, if they do have an effect on the central nervous system, understanding that influence could open the door for more comprehensive, and perhaps more specific, therapies to treat congestive heart failure, and heart disease in general.

Neuroscientifically Challenged

Neuroscientifically Challenged is a neuroscience learning resource. In addition to a blog that discusses science current events in a non-technical manner, you will also find a number of videos and articles that you can use to learn about basic principles of science and the brain.